Do not hide membership of implementation classes in dart:core.

runtime/lib/mirrors.cc

Index: runtime/lib/mirrors.cc
diff --git a/runtime/lib/mirrors.cc b/runtime/lib/mirrors.cc
index 21000a9a7c705c9582ab568441d843694c0a9119..07029a2e6af5d6917e9b8fcb9a374ff571385156 100644
--- a/runtime/lib/mirrors.cc
+++ b/runtime/lib/mirrors.cc
@@ -1117,11 +1117,10 @@ DEFINE_NATIVE_ENTRY(LibraryMirror_members, 2) {
     entry = entries.GetNext();
     if (entry.IsClass()) {
       const Class& klass = Class::Cast(entry);
-      // We filter out implementation classes like Smi, Mint, Bignum,
-      // OneByteString; function signature classes; and dynamic.
+      // We filter out function signature classes and dynamic.
+      // TODO(12478): Should not need to filter out dynamic.
       if (!klass.IsCanonicalSignatureClass() &&
-          !klass.IsDynamicClass() &&
-          !RawObject::IsImplementationClassId(klass.id())) {

[rmacnak, 2013/10/14 21:18:03]

We originally filtered these out because we were using UserVisibleName as the
key for classes. In the version of mirrors that used the embedding API,
superclasses and interfaces were looked up by name rather than by reference, and
we got into problems where, say, OneByteString would be added to the core
library's members after String and replace it in the map and produce incorrect
results. Now that we are properly looking for superclasses, interfaces, etc by
reference and we aren't using UserVisibleName, we can correctly admit to the
membership of these classes.

+          !klass.IsDynamicClass()) {
         type = klass.RareType();
         member_mirror = CreateClassMirror(klass,
                                           type,